Patients treated at the hospital by the infected worker have been invited to attend special clinics to give blood samples for testing. The hospital has said it does not expect to find any patient has been infected through treatment at the hospital in Frimley. At a press conference on Friday, chief executive of Frimley Park Hospital Trust Andrew Morris refused to identify the infected member of staff for confidentiality reasons but confirmed the person could have been infected “for a number of years”. Dr Corry van den Bosch, a consultant in communicable diseases, said hepatitis C was a blood-borne virus more infectious than HIV. The condition can remain in the bloodstream for 20 years unknown to the carrier and can cause liver failure if left untreated. The member of staff was found to be hepatitis C positive in March following a voluntary blood screening test. The worker was immediately removed from duties that might have put patients at risk of infection. Explaining the three-month delay in contacting patients, spokesman John Skillicorn-Aston said advice was taken from the UK Advisory Panel. “The trust had to examine notes of a large number of patients to see if the worker had undertaken certain procedures on them,” he said. Mr Morris sought to reassure the public and said the trust had gone beyond the guidelines suggesting the hospital contact 500 patients. He said: “This is very much a precautionary measure. We don’t expect to find transmission to any significant degree.” Around 85 per cent of infected individuals go on to develop chronic or ongoing hepatitis C infection. The progression of the disease varies from person to person and some people may never experience symptoms. Others may experience extreme tiredness and nausea 10 to 15 years after infection and a significant minority develop serious liver disease. Around 10 per cent of children born to hepatitis C infected mothers will contract the virus. One Frimley Park patient, who did not want her identity revealed, was one of the 782 who received a letter and is 12 weeks pregnant. She spoke of her concern, not only that she might be infected, but that her husband and two small children were also at risk. She is now worried about returning for future appointments. She said: “I’m upset and angry. As far as I’m concerned, it’s put us all at risk and I’m worried about going back to the hospital. “Taking the worst case scenario, if I have got this disease then there’s a chance my baby could be born hepatitis C positive.” She added she was disappointed with the letter that contained no information on the virus, yet the hospital had claimed a fact sheet was enclosed. “It’s a stress I don’t need. You have faith the system will look after you but I have completely lost my faith in the NHS. You go into hospital to get better, not to come out with something else.”